I don't think defence forces bases figure very highly in the SNP agenda; they probably recognise that they couldn't run their own RN,RM, Army, RAF and SF.
So if they decide to remove themselves from the union they would probably decide to retain a joint defence force with the rest of the UK.
Also they would probably want to retain the jobs, commercial and financial benefits to the Scottish communities close to the bases (not just RAF but RN, RM, Army and SF).
Message is - Scottish independence probably wouldn't affect the defence community.
Best wishes SOS